Question

I am relatively new to programming and databases.

I have a MySQL database with a “sales” table. This table lists all sales in a state (i.e. each record is a particular sale), with fields for sellername, and buyerzip. I would like to have another table “seller” that would include sellername, and also include fields to define the sellers market area by zip code – say 50+ zip codes define a market, and the seller could define multiple markets.

These market areas would be used for future queries: showing all sales in a particular market area.

Where do I start in terms of thinking how to store that “market area” data, and then use it for future queries?

Thanks

Answer 1

Table structure:

• Sales table: ID, sellerID, buyerZipcode, amount
• Seller table: ID, sellerName
• Market table: ID, marketName
• SellerMarketLink table: ID, sellerID, marketID
• MarketZipCode table: ID, marketID, zipCode

Example data

Encoding the information in the first comment to your question

Market table

1, “Store A, first market”
2, “Store A, second market”
3, “Store B market”

MarketZipCode table

1, 1, 1
2, 1, 2
…
7, 1, 7
8, 1, 8
9, 2, 4
10, 2, 5
…
14, 2, 9
15, 2, 10
16, 3, 1
17, 3, 2
18, 3, 3
19, 3, 8
20, 3, 9
21, 3, 10
22, 3, 11
23, 3, 12

Query

Total sales in a market for each seller. Note that since one zip code can be part of several markets, the total of all values in “Total Sales” can be larger than the sum of all ‘amount’ values in the Sales table.

select Market.marketName, Seller.sellerName, sum(Sales.amount) as "Total Sales"
from Sales join Seller join SellerMarketLink join Market join MarketZipCode
on (Sales.sellerID = Seller.ID AND Seller.ID = SellerMarketLink.sellerID 
  AND SellerMarketLink.marketID = Market.ID 
  AND Market.ID = MarketZipCode.marketID 
  AND MarketZipCode.zipCode = Sales.buyerZipCode)
group by Market.ID, Market.marketName, Seller.ID, Seller.sellerName
order by Market.marketName, Seller.sellerName